Catalytic oxidation of crude anthracene



Patented Sept. 12, 1933 UNITED STATES PATENT", Fries? '8 Claims. (01'. 260-57) This invention relates to the. production of anthraquinoneby the catalyticoxidation of crude anthracene. I

mmy prior application Serial No. 228,977,.

5 which is now Patent No. 1,846,728, issuedDe cember 26, 1930, filed Oct. 26, 1927 processes for purification of crude aromatic .compounds'ineluding crude anthracene have been described, in which the anthracene is purified by selective catalytic oxidation of impurities, the process being carried out in the presence of catalysts which favor oxidation of the impurities, but.

which do not favor theoxidation of anthracene to anthraquinone. In my co-pending application Serial No. 264,571, filed March 24, 1928, which is a division of Patent No. 1,709,853 dated April 23, 1929, processes for the production of anthraquinone are described in which similar stabilized combustion catalysts which favor the oxidation of impurities but not the oxidation of anthracene are used in conjunction with anthraquinone catalysts. This application, of which the present case is a continuation in part, discloses only the production of anthraquinone from semipuriiied anthracene, the semi-purified product being in some cases produced by the catalytic purification ofcrude material.

In my application Serial No. 301,693 which is now Patent No. 1,880,322,jissuedOctober.4, 1932 for the production of anthraquinone is proposed, one function of the alkali being to decompose carbazol, but thisapplication also discloses only the production of anthraquinone :from semipurified anthracene. i

' The present'invention is based on'thcsurprising discoverythat crude anthracene as sold on the market, and containing all'the phe'nanthrene, carbazole, dead oils, chrysene, retene, methyl anthracene, diphenyl, pyrene, acridinei andother impurities, ranging in amounts from more than oneto 5 times the; weight of the anthracene filed August 23, 1928, the use of alkaline catalystsv bustion components for the undesiredimpurities and oxidation components for theproduction of anthraquinone from the anthracene, a product can be obtained, which can be directly used for many of the purposes for which anthraquinone from other sources is now employed, and particularly for the production of alizarin.

The preferred catalysts for the production of anthraq'uinone from crude anthracenes contain stabilizers to limit the total oxidation of anthracene to carbon dioxide and water, and I have found that by the use of proper amounts of these substances, with or Withoutthe additionof suitable stabilizer promoters, the activity of the oxinearly the aliphatic compounds in its stability. v

towards oxidation and is'much more readily decomposed than anthracene, These' two substances are the chief impurities present in crude anthracene andare by far the most stable, and

no difficulty is encountered in oxidizing the other 3 impurities present when [catalysts are. employed which will oxidize these" two compounds. I The 'catalyti'cally active-elements which may be used for oxidizing the anthracene -to'anthraquinone in the composite catalysts employed in the present processmay bemetals of the 5th, 6th and some members of the 8th groups'oftheperi f odic system, together with stabilizer promoters selected from the metals of the 3rd to the 8th groups of the periodic system inclusive. The 9 H term stabilizer promoter.is intended to cover substances which; are ca alytically active, 'but which do not'possess specific catalytic activity forthe oxidation of anthracene to anthraquinone under the. conditions. used in the reactiomand 9 which substances promote the reaction by ex tending the action of the stabilizer. :Ironand copper are particularly useful stabilizer promote ersfor this purpose, and may be used in conjunctionwith any of the stabilizers, which are,

as is well known, compounds of the alkaliforming metals, 1. e. alkali and alakaline earth metals..-

Reference has been made to' combustion catalysts and oxidation catalysts for anthracene,

as if these were separate-constituentsof the con- 111.0

of the more difficulty oxidizable anth'racene to carbon dioxide and water, a certainbeneficial influence on the amount of total 'combustion of the anthracene. The comparatively small amount of total combustion of this sub:

stance may also be due in part to the blanketing action of large amounts of substances other than anthracene and oxygene in the reaction gas mixture, but irrespective of any theory as to the mechanism of the reaction,'the-fact remains that commercitlly useful anthraquinone can be obtained in good yields from crude anthracene of as low as 15-26% anthracene coiitentjby' the action 2"5 of catalysts sufliciently powerful to oxidize the tremendous amount of impurities present, with-. out serious amounts of total combustion of the anthracene itself. The invention is notlimited,

however, to the use of catalysts which have a combined action on the anthracene and impurities, but on the contrary substances such as cerium oxide, titanium'oxide, aluminum, thorium oxide, copper oxide, nickel oxide, cobalt oxide,

and the like, which have little if any catalytic power in the oxidation of anthracene to anthraquinone, can be used as combustion catalysts in conjunction with catalysts for the partial oxidation of anthracene. Such catalysts are prefer.-

ably stabilized, and when large amounts of carbazol are present the use of alkaline stabilizers aids in the decomposition of this substance as well as in the production of anthraquin'one from the anthracene. f I

Since in many cases considerable amounts of 'material mjustbe oxidized in order to obtain commercial amounts of anthraquinone, and since a number of strongly exothermic reactions are progressing simultaneously, it is necessary to .use

I powerful temperature regulating means to con.-

trol the course of the .anthraquinone reaction. Converters of the bath type in which catalyst tubes are in heat exchangingrelation with a circulating, non-boiling bath or with a bath which combustion of the impurities should, as a general rule, be somewhatlowerthanthose usedin the corresponding oxidation of pure or semi-purified anthracene, for the excessive heat evolution resuiting from the tremendous amount of total combustion makes it necessary tojuse as high a heat head aspossible between the bath and the catalyst. In general, bath temperatures higher than 550 C. should not be used, and with most catalysts it is preferable to use bath temperatures of 280- 160? C., depending'upon the amount of impurities in the crude material, the type of catalyst used, and other factors of the reaction. Since crude anthracene sold on the market may vary considerably in relative content of anthra- This combined acticnQis. probably due to in composition by distilling off fractions of the of treatmentwill be described in the following examples. In general, the most efficient method of separating the anthraquinone from such large amounts of gaseous reaction products is the use of fractional condensation in condensers having positive temperature control. Rapid cooling of the gases leaving the converter, followed by sublimationor distillation" of the anthraquinonemay also be used, as well as solventmethods such as those using furfural or other 'heterocyclic solvents described in my prior application Serial No. 296,869, filed Augustl, 1928. e

The 'invention'will be described in greater detail in the following examples, which are for iilustrative purposes only and to; which it is not limited. I

' Example 1 A catalyst is prepared as follows:

, 18. 2 parts'of V205 are dissolved in a solution containing 22.6 parts by weight of 100% KOH together with 240 parts of water. The potassium vanadatesolution soformed is stirred into a solution containing 5.6 parts MnSO42H2O and 22.65 parts Fe2(SOi)3 in 300 parts water. The precipitate so formed is filtered with suction, washed, and sludged up with 33 parts by weight of con centrated sulfuric acid dissolved in 200 parts of water, and the suspension sprayed onto 1250 parts by weight of pumice of 610 mesh particle size. f

.A crude 'anthracene of 40-45% anthracene content,obtained from the distillation of tar from an American coaland containing appreciable quantitiesof phenols, naphthalene, and other substances which would interfere with a solvent purl .fication, as well as 17-22% carbazol and 3l-38% phenanthrene is vaporized with air at 200-260" C. in a ratio: of 1 part crude anthracene to 30-50 parts by weight of air, and passed over the contact mass. The mass is retained in a tubular converter,

the catalyst tubes being surrounded by a nonboilingbath consisting of a eutectic mixture of sodium nitrate and sodium nitrite, and the bath is maintained art-temperatures of 380-440 C. by suitable temperature regulation. The effluent gases from the converter are led into a series of condensers, the first beingsteam jacketed with steam under 120 pounds, the second with steam at about 100 pounds, the thirdat aboutBO pounds and the fourth being a box condenser designed to permit separationof the remaining solid material.

An anthraquinone of 92-96% purity is recovered from thefirst condenser, which is directly usable without further purification for sulfonation to silver salt, as described in the co-pending application of Jaeger and West, Serial No. 526,135, filed March 28, 1931. In the second condenser a. product is obtained of 83-91% purity, from which 1 a commercially usable product can be obtained Example 2 Potassium vvanadate, prepared by dissolving 10 parts by weight of V205 in a solution containing 7 parts of 100% KOI-I and 150 parts of water, is.

reacted with ferric chloride prepared by dissolving 5.84parts F6203 in 11 parts concentrated hydrochloric acid diluted with 50"parts water. The precipitate is filtered and washed and suspended in 250 parts of water so that a fine suspension is obtained, which is sprayed onto 500 partspeasized pumice stone. The catalyst so obtained is calcined with air at 450 C. and then with dilute S02 gases, after which it is-again blown outwith air. v

A crude anthracene of -40% purity is vaporized by spraying into.a current of air at 240-280 C. and passed over the catalyst, which is retained in a tubular convertersimilar to that described in Example 1 and having a bath temperature 340- 400 C. The vapors from the converter are led to a fractional condenser similar to that in the preceding example, and an anthraquinone of 90-95% purity is obtained in the first chamber. A product of 83-90% is obtained in the second chamber, and a product of 30-l5% anthraquinone on the dry basis with 1.6-3.1 moisture content is obtained in the thirdcondenser. The tailings from this process as collected in a box condenser contain 15% anthraquinone on the dry basis together with moisture. g

The above described catalyst'may be stabilized by incorporating alkali or alkaline earth metal compounds with the ferric vanadate suspensionbefore spraying, or an alkaline stabilizer such as potassium or calcium hydroxide may be used if 1., A process of producing anthraquinone which comprises passing vapors of crude anthracene in admixture with an oxidizing gas at reaction temperatures over a contact mass containing a catalyst for the vapor phase oxidation of organic compounds and also containing at least one-compound of a metal included within the group-consisting of alkali metals, alkaline earth metals.

2. A process of producing anthraquinone which comprises passing vapors of crude anthracene, in

admixture with an oxidizing gas, at reaction temperatures-over a contact mass containing componentsfavoring the oxidation of anthracene to anthraquinone and components favoring the combustion of impurities and also containing at least one compound of a metal included within the group consisting of alkali metals, alkaline earth metals. 3. A process of producing anthraquinone which comprises passing vapors of crudeanthracene, in admixture'with an oxidizing gas, at reaction temperatures, over a contact masscontaining components favoring the oxidation of anthracene to anthraquinone and components favoring the. combustion of impurities and also containing at least one compound of a metal included within the group consisting of alkali metals, alkaline pound.

4. A process according to claim 1, in which the reaction mixture contains more than fiveparts by weight of oxygen to one part by weight of crude anthracene vapors. Y

5.3A process according to claim 2, in which the reaction mixture contains more than five parts by weight of oxygen to one part by weightof crude anthracene vapors.

6. A process according to claim 1, in which the catalyst contains a compound of vanadium.

'7. A process according to claim 2, in which the catalyst contains a compound of vanadium.

.8. A process according to claim 2', in which the tion and also iron in chemical combination.

ALPHONS O. JAEGER.

catalyst contains'vanadium in chemical combinaf V 

